Fireplace with air-heating tubes therein



April 17, 1951 J. BORGE 2,549,365

FIREPLACE WITH AIR HEATING TUBES THEREIN Filed May 21, 1946 2 sheets-sheet 1 .Fk l 5 ATTORNEY? April 17, 1951 BQRGE 2,549,365

FIREPLACE WITH AIR HEATING TUBES THEREIN Filed May 2 1, 1946 2 Sheets-Sheet 2 .sMo/rE CHAMBER C010 A/E Q I AVI/ENTOE [tr/6.3 20 firm/v BOEGE.

J ,wwlmwg Patented Apr. 17, 1951 orricr.

FIREPLACE WITH AIR-HEATING TUBES THEREIN Johan Borge, Bellport, N. Y.

Application May 21, 1946, Serial No. 671,235

1 Claim.

This invention relates to new and useful improvements in open fireplaces, generally, and more particularly to such a fireplace having means embodied therein for heating and circulating air within a room or other enclosure.

Generally speaking, ordinary open fireplaces do not have a great deal of utility, except from an ornamental point of view, because in most conventional fireplaces a large percentage of the heat is 'lost through the stack or fiue because of the inherent suction in the flue and the fact that the fireplace is usually in direct communication with the flue. Dampers are usually provided in conventional fireplaces to control the draft, but in most cases these must be left fairly wide open when the fireplace is operating in order to prevent the escape of smoke from the fireplace into the room in which the fireplace may be located.

Numerous attempts have been made in the past to improve the efficiency of open fireplaces by embodying therein a heating chamber through which a portion of the cold air in the room may be circulated for the purpose of increasing the heating efilciency of the fireplace. Some of these past installations have proven more or less eflicient, but they have been objectionable for constructional reasons and for various other reasons, as, for example, cleaning. Conventional fireplaces are usually provided with smoke shelves and may have other ledges upon which soot may accumulate, and if the soot is not periodically removed therefrom, such soot may impair the efiiciency of the fireplaces.

An object of the present invention, therefore, is to provide a fireplace in which all of the objectionable features now present in conventional fireplaces have been removed, with the result that the fireplace herein disclosed presents the utmost in efiiciency and economy, is extremely simple to operate without danger of smoke escaping into the'room, and which involves no erection difficulties, whereby it may be quickly and inexpensively constructedby unskilled labor.

A further object of the invention resides in the provision of a fireplace having embodied therein a series of air-heating tubes which are uniquely arranged therein to provide the back and side walls of the fireplace or hearth, and whereby such tubes are exposed directly to the products of combustion with the result that their walls may be quickly heated to a relatively high temperature, and said tubes being in communication with the room at diiferent levels, whereby they will have a stack efiect upon the incoming air, and thereby cause the incoming cold air adjacent to the floor to :be quickly ciriculated upwardly through said hot tubes, whereby the air is heated and returned to the room at a relatively high temperature. By reason of the above-described construction, my improved fireplace, in addition to serving the usual function of a fireplace, also serves to provide an auxiliary hot-air heater, which, because of its novel design, will absorb most of the B. t. u.s from the products of combustion, resulting in low stack temperature and relatively greater economy.

A further object of the invention is to provide a combination fireplace and hot-air heater comprising a combustion chamber, the back and side walls of which are composed of a plurality of vertically disposed, closely spaced air-circulating tubes, and the top wall of the fireplace being in the form of a draft equalizer, comprising a plurality of horizontally disposed spaced fixed bars {and a series of complemental spaced bars constructed to be moved into registration with the fixed bars, thereby to provide a series of smoke passages throughout the entire area of the top wall of the fireplace, through which smoke may pass from the fireplace to the usual stack or flue, said movable bars, when in registration with the fixed bars, being streamlined in cross-section to induce free flow of the products of combustion from the fireplace to the stack or flue, and said movable bars also serving to control the flow of the products of combustion to the stack, and to equalize the draft through the openings in the entire top wall of the fireplace.

A further object is to provide a fireplace comprising back and side walls and a top wall, the top wall being constructed to provide a draft equalizer for controlling the flow of the products of combustion from the fireplace into a smoke chamber provided over the fireplace, and the upper portion of the smoke chamber being connected to the usual stack or flue through a restricted passage or throat simulating a Venturi tube, which serves to prevent down-drafts and eddy currents in the flow of the smoke and gases from the fireplace to the flue, whereby the danger of smoke escaping from the fireplace into the room, even when the draft equalizer may be nearly closed, is substantially eliminated, said Venturishaped smoke passage causing a uniform suction through all of the damper-like openings provided in the upper wall of the fireplace, which is of extreme importance in an open fireplace.

Other objects of the invention reside in the construction of a combination fireplace and air heater which is extremely simple in construction, whereby it may readily be constructed by unskilled labor with the assurance that the fireplace, when compieted, will be efficient and practical in operation; in the provision of such a fireplace whose back and side walls are composed of a plurality of closely arranged upright air-circulating tubes, all of which are alike in construction, whereby such tubes may be manufactured in quantity production at low cost; and in the provision in an open fireplace of an airheating and circulating means which is highly efficient and practical in operation, is extremely simple and inexpensive in construction, and which has no smoke shelves or ledges upon which soot may accumulate, as in conventional fireplaces.

Other objects of the invention will appear from the following description and the accompanying drawings and will be pointed out in the annexed claim.

In the accompanying drawings, there has been disclosed a structure designed to carry out the various objects of the invention, but it is to be understood that the invention is not confined to the exact features shown, as various changes may be made within the scope of the claim which follows.

In the drawings:

Figure 1 is a sectional view on the line l-l of Figure 2, illustrating the front of my improved fireplace and also showing the cold and hot-air ducts connected together by the air-circulating tubes constituting the back and side walls of the fireplace;

Figure 2 is a sectional plan view on the line 22 of Figure 1;

Figure 3 is a sectional elevation on the line 3-3 of Figure 1;

Figure 4 is an enlarged detail sectional view showing a portionof the draft equalizer in wide open positions; and

Figure 5 is a view similar to Figure 4, but showing the draft equalizer in closed position.

The novel apparatus herein disclosed is shown comprising an open fireplace 2 having a back wall A, side walls B, and the usual hearth C. The back and side walls A and B, respectively, are formed by a plurality of upright air-heating tubes 3 and 3, respectively, arranged in side-by-side relation with the Walls of adjacent tubes preferably contacting one another, as best illustrated in Figure 2.

The upper and lower end portions of the airheating tubes 3 and 4 are shown supported in suitable masonry, generally designated by the numeral 5, whereby they are fixedly supported in upright positions, as will be understood by reference to Figures 1 and 3. Suitable fire-proof and heat-insulating bricks 6 may be embodied in the masonry 5 adjacent to the upright aircirculating tubes 3 and 4 to minimize the loss of heat by conduction to the masonry 5. In actual operation, however, I have found that the loss of heat by conduction from the air-circulating tubes 3 and 6 to the masonry 5 is negligible. The masonry 5 may be of any suitable construction, applicable for the purpose.

The tubes 3 and l constitute an important feature of the present invention. As best shown in Figures 1 and 2, the lower ends of said tubes are in communication with opposed cold-air intake ducts or chambers 1 provided in the masonry 5 at the floor level of the fireplace at each side thereof. These cold-air chambers are shown separated from one another by a wall 8 which may be a part of the masonry 5 providing the supporting structure for the fireplace.

By reference to Figures 1 and 3, it will be noted that all of the air-circulating tubes 3 and 4 are cut away at their lower ends a distance extending upwardly from the bottom walls 9 of the coldair chambers to the top walls of said chambers, and to substantially one-half the diameter of each tube, whereby maximum fiow of cold air may pass from the cold-air intakes upwardly through the air-circulating tubes, as indicated by the arrows in Figures 1 and 3.

Similarly shaped hot-air discharge ducts or chambers [2 are provided at the upper ends of the air-heating tubes 3 and 4 and are in communication with said tubes in a manner similar to the cold-air chambers l, as will be best understood by reference to Figure 1. The hot-air chambers l2l2 are separated from one another at the back of the fireplace by a partition 8 similar to the cold-air chambers 1-7. Suitable registers 13 may be provided in the intake openings of the cold-air chambers 1-'l, and similar registers M are provided in the discharge openings of the hot-air chambers l2l2.

By reference to Figures 1, 2, and 3, it will be noted that the air-heating tubes 3 and 4 are all substantially alike in construction, whereby these tubes may be manufactured in quantity production at low cost. In the erection of the fireplace, the tubes may be independently arranged to pro vide the back and side walls of the fireplace, or, if desired, the'tubes constituting each side wall B may be welded together to provide a single unitary structure, and in like manner all of the tubes constituting the back wall A may be welded together as a unit. From actual experience, however, I have found that the air-heating tubes 3 and 4 may readily be independently erected in the construction of the walls A and B of the fireplace without any difficulty. If desired, means, not shown, may be provided in the cold or hot-air intake and discharge openings for controlling air circulation therethrough.

Another important feature of the invention resides in the means provided for conducting the smoke or products of combustion from the fireplace 2 to the usual fiue or stack. As best shown in Figures 1 and 3, a smoke chamber [5 is provided directly over the fireplace, and has its front and back walls l6 and I1, respectively, inclined inwardly from the front and back of the fireplace, as shown in Figure 3. In like manner, but at a relatively greater angle, the side walls l8 of the smoke chamber are inclined inwardly, whereby they cooperate with the front and rear walls l6 and I! of the smoke chamber to provide a restricted throat-like smoke passage 19, which tapers outwardly in an upward direction as shown at 2| in Figures 1 and 3, thereby to provide in effect a Venturi-shaped smoke passage connecting the smoke chamber 15 with the usual flue or stack 22 of the fireplace.

The construction of the smoke chamber l5 and the Venturi-shaped smoke passage l9, connecting it to the usual stack 22, is of utmost importance, in that it positively prevents the formation of down-drafts and eddy currents in the smoke chamber, whereby smoke leakage into the room is substantially eliminated, even when the draft equalizer, subsequently to be described, is in a nearly closed position. The Venturi-shaped smoke passage IS, in addition, causes a uniform suction through all of the smoke passages provided in the damper-like top wall of the fireplace, whereby the smoke is uniformly drawn from the fireplace over the entire area of its top wall into the smoke chamber, from whence it passes through the restricted throat or Venturi-shaped allel bars 23. The lower portions of the bars 23 are substantially semi-cylindrical in shape, and said bars 23 may readily be cast or fixed ina suitable frame 24 to facilitate fixedly mounting the bars 23 in the masonry, as will be understood by reference to Figures 1 and 3. The upper faces of the bars 23 are shown disposed in a horizontal plane, as best illustrated in Figure 5.

Operating in conjunction with the spaced bars 23 of the draft equalizer D to control the flow of smoke or the products of combustion from the fireplace to the smoke chamber I5, is a second grill-like structure or frame, generally designated by the numeral 25. This grill-like structure comprises a plurality of horizontally disposed spaced bars 26 adapted to be moved into registration with the lower bars 23, as shown in Figure 4, thereby to provide maximum flow of the smoke and gases from the fireplace to the smoke chamber. The grill-like frame 25 is shown provided with a suitable handle 2'! which may be supported in a guide opening in the wall of the masonry 5, as shown in Figure 1, whereby an attendant may readily shift the position of the draft equalizing bars 26 of the member 25 with respect to the lower fixed bars 23, thereby to vary the sizes of the draft openings 28 provided between the spaced fixed bars 23.

Another important feature of the invention resides in the cross-sectional shapes of the bars 23 and 25, which are such that when the upper movable bars 26 are moved into registration with their fixed bars 23, as shown in Figure 4, the cross-section of each combined bar 23 and 26 will be fully streamlined, as shown in Figure 4, thereby to minimize resistance to the flow of the products of combustion through the elongated smoke passages 28, when said passages are open.

In the operation of the novel fireplace herein disclosed, a fire is started on the hearth C of the fireplace in the usual manner. Upon initial starting of the fire, the draft equalizer or damper 25 is shifted to its open position, as shown in Figures 1 and 4, thereby to provide maximum air circulation or draft through the top wall of the fireplace composed of the grill-like structures 23 and 25. If desired, a suitable grate may be placed on the hearth C for supporting the fire, and a suitable ash dump may also be provided in the bottom wall or hearth of the fireplace, as indicated at 26 in Figures 2 and 3, which may be in communication with a suitable chute or duct, not shown. The use of a grate is optional, as obviously the fireplace will function without such a device.

As the fire gradually gets under way, the Walls of the air-heating tubes 3 and l, constituting the back and side walls A and B of the fireplace, become heated. Such heating of the tube walls immediately creates a circulation of cold air upwardly through the tubes, as indicated by the arrows in Figures land 3. The cold air thus drawn into the air-circulating tubes enters the cold-air chambers 2-! through the registers [15, which are in communication with the atmosphere at floor level. As the air circulates upwardly through the tubes, it is quickly heated and is delivered into the hot-air chambers [2 at opposite sides of the fireplace. From the chambers 12-4 2, the heated air is discharged into the room from opposite sides of the fireplace, as indicated by the arrows in Figures 1 and 2. It will thus be noted that the novel fireplace herein disclosed comprises no smoke shelves or other horizontal ledges upon which soot and other foreign matter may accumulate. The interiors of the air-heating tubes are not directly exposed to the products of combustion, and the webs of the smoke chamber l5 are so constructed that soot and foreign matter cannot lodge thereon. The same applies to the draft equalizer bars 55 and 23. These bars, it will benoted by reference to Figures 4 and 5, are so shaped, crosssectionally, that there is little or no danger of any soot or foreign matter accumulating thereon. It will thus be noted that the fireplace herein disclosed is substantially self-cleaning and is extremely inexpensive and economical to erect and maintain, and, in addition, it provides a very eilicient and economical air heater which readily lends itself for use in homes and the like as an auxiliary heating means to an open fireplace.

The Venturi-like smoke passage connecting the smoke chamber 15 to the flue 22 assures ample draft or suction from the fireplace into the smoke chamber [5 at all times Without any danger of developing down-drafts and eddy currents. The tubes may be made from any suitable material and of any particular size applicable for the particular job to which the fireplace is assigned, and they are substantially self-cleaning, which is a highly desirable feature in a fireplace structure.

The upright air-heating tubes 3 and 4 provide a maximum surface area which is exposed directly to the products of combustion, whereby the walls thereof become quickly heated to thereby initiate prompt suction of cold air into the cold-air ducts and through the tubes 3 and 4 and hot-air ducts or chambers l2. While only one-half the .wall of each tube is directly exposed to the products of combustion, the back walls of the tubes become quickly heated by conduction, and when insulating bricks are used in the masonry for supporting the back walls thereof,

as shown at the right-hand side of Figure 1, there is very little heat loss by conduction to the masonry.

It will be apparent to those skilled in the art that I have accomplished at least the principal objects of my invention, and it will also be apparent to those skilled in the art that the embodiments herein described may be variously changed and modified without departing from the spirit of the invention, and that the invention is capable of uses and has advantages not herein specifically described; hence it will be appreciated that the herein disclosed embodiments are illustrative only and that my invention is not limited thereto.

I claim:

In a combined fireplace and air heating device a columnar body provided with a fireplace opening and a smoke outlet passage therefor; said fireplace opening being defined by a hearth, side l walls and a back wall; said body being provided with cold-air passages adjacent said hearth and extending along the lowermost portions of said back and side walls, and with hot air passages adjacent the top of said fireplace opening and extending along the uppermost portions of said back and side walls; said body being further provided with inlet passages for admitting cold air to said cold-air passages and outlet passages for conducting hot air from said hot air passages; said back and side walls comprising a bank of vertically disposed tubes each being in contact with the tubes adjacent thereto; said tubes each being provided With an opening in the side wall adjacent the lowermost end thereof communicating with said cold-air passage and each being further provided with an opening in the side wall adjacent the uppermost end thereof communicating with said hot-air passage whereby said tubes may receive heat from said fireplace and initiate an updraft of air through said tubes thereby producing a circulation of REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,273,695 Unsworth July 23, 1918 1,519,218 Richey Dec. 16, 1924 5 1,707,096 Rich Mar. 26, 1929 1,763,076 Walters June 10, 1930 1,987,252 Cage Jan. 8, 1935 FOREIGN PATENTS 20 Number Country Date 457,705 Great Britain Dec. 1, 1936 

